ABSTRACT: Three-phase power-flows are used to analyze three-phase unbalanced networks. The unbalanced condition exists in both power system components as well as operation of power systems. This condition is due to many causes such as unbalanced loads, long untransposed high voltage lines in transmission networks, presence of single-phase lines or two-phase lines, or both type of lines, in a three-phase distribution networks. Therefore, threephase power-flow methods are traditionally implemented based on complete phase component modeling [1-10]. For fast execution time, some of these methods consider primarily the radial structure of distribution networks [8-10]. They can only solve radial or weekly meshed distribution systems, which mean that they cannot solve unbalanced transmission systems.